PREFERENCE COMMUNICATION IN MULTIATTRIBUTE PROCEDURES FOR OPTIMIZED SHIP DESIGN

Multi-Attribute decision-making procedures are nowadays utilized in technical, social, and economical applications when the simultaneous consideration of several parameters - or criteria - is necessary to develop optimised design proposals or to rank existing designs. Some applications have been presented in the marine field and the method is taking increasing consideration also in the professional practice, to develop or to identify the best proposal at basic design stage. One of the most important aspects of these procedures is represented by the designer preference communication, generally performed in terms of different weights to be assigned to the chosen design attributes. While quite intuitive and rather effective in most of cases, this approach is capable of noticeably influencing the final result. The relative importance assigned through the attribute weights to different design criteria affects the rank of the proposed alternatives and therefore the features of the design to be chosen as the best one. As this is the key factor for a successful implementation of Multi-Attribute procedures, some techniques have been developed to better perform the attribute weight assignment. Particularly, the subjective and objective importance of each attribute has been considered within the integrated approach proposed by Ma-Fan-Huang in 1998. The main feature of the Ma-Fan-Huang method is the assignment of weights on the basis of both the designer subjective preferences as well as the objective information included in the attribute values. In this paper a flow chart of a multiattribute procedure suitable to ship design is presented and a routine to calculate the weights through the Ma-Fan-Huang method is supplied. A practical application is carried out applying the presented routine to the multiattribute ranking of mono and multihull design proposals for a small passenger fast ferry. Technical, economical and commercial attributes have been considered. Technical attributes are limited to resistance, and seakeeping design moduli, as the most meaningful ones with regard to ship performances; economical attributes are relative to construction and operational costs; commercial attributes are selected on the basis of data collected through passenger interviews. The suitability and the potential of Ma-Fan-Huang method for preference communication in multi-attribute ship basic design is shown and a reference is provided for further applications of multiattribute procedures to ship design.